In Your Room
by Cocobel
Summary: Derek Venturi and Casey McDonald are complete and total opposites. Just like their bedrooms. But. You know what they say about opposites.
1. Chapter 1

**In Your Room**

Her bed faces her door. His is against the same wall as his door. Hers is sunny, bright, colorful. His is dark, less welcoming, more brooding. Hers? Perfectly organized. His? Organized chaos.

Much like their relationship.

 _What relationship?_ He blows out a breath and deftly catches in one hand the hockey puck he's been flinging into the empty space above his head, over and over. Aside from the vicious cycle of pranking and fighting and _"DER-_ _ **EK**_ _!"_ there is…nothing. They have nothing. Just a thin wall to separate their bedrooms and a blended family to tie them together, forever, _'til death do GeorgeandNora part_. That's all. It's not complicated.

 _It's complicated_ , she sighs to herself, in the next room with a book in her lap, a manicured finger touching the page below the single sentence she's been reading, over and over. But _what_ is complicated? Certainly not them. They are step-siblings and nothing more…but then, she can't help but wonder, because something _feels_ complicated about…she doesn't even know, she can't put her finger on it, but, _something_ …could it have anything to do with that tiny little modifier…that, they each must have noticed, they _both_ feel compelled to inject into any conversation where anybody refers to them as _siblings_? Because they are _step-_ siblings.

And the commonalities end there—almost sooner than they begin—because other than that, Derek Venturi and Casey McDonald are complete and total opposites. Just like their bedrooms.

 _But. You know what they say about opposites._


	2. Chapter 2

**–** **2 –**

" _DER-_ _ **EK**_ _!_ "

All at once, George and Nora, Edwin, Lizzie, and Marti all sigh, roll their eyes, and throw back their bedcovers, knowing there will be no more quiet in the McDonald-Venturi household this morning.

The exception is Derek Venturi. The exception is always Derek Venturi. As Casey's shriek reverberates down the hallway, he yawns, stretches, and laces his hands behind his head, trademark smirk settling on his lips. A split second later, his bedroom door flies open and Casey seethes over him, dressed in pajamas with her hair still tied up in last night's ponytail, and…an unnatural shade of blonde.

"Huh." He looks her up and down. "Blonde's not bad on you, Space Case." He reaches out to tug on her bleached ponytail and she smacks his hand away. His smirk stretches into a wide grin. "Or should I call you Head Case?"

"Urgh!" She yanks the pillow out from behind his head and smushes it into his face as hard as she can until he kicks her away. "What the hell is _wrong_ with you!? I can't go to school like this!"

"What, I thought I was doing you a favor!" His brown eyes gleam mischievously. "I heard Max likes blondes."

"Der- _ **ek**_ , you read my diary!? I'm going to _kill_ you!" She lunges for him but he's ready for her, catching her by the upper arms and using her momentum to flip them so that she lands on the bed underneath him, and he easily pins her down even as she struggles, blue eyes glaring determined daggers.

At the foot of the staircase that ascends to the attic, Edwin covertly videotapes the teenagers while Lizzie scribbles into a black binder. More material for their secret files.

"What is going on up here?" Nora climbs the stairs, tightening the belt on her bathrobe, George stifling a yawn right behind her. At the first sign of parents Edwin flees up his stairs and Lizzie slams her bedroom door; the adults barely notice as they shuffle reluctantly closer to the red door with the KEEP OUT sign.

"Derek put bleach in my leave-in conditioner!" Casey yells, still trying to gain the upper hand. She finally brings her knee up and shoves against Derek's chest. He winces, and she kicks him off the bed, but as he hasn't released her arms she goes with him, and scrambles up off him as soon as they realize what position they ended up in.

"Derek!" Both parents glare at him disapprovingly.

"I can't go to school looking like this!" Casey complains. "I can't leave the _house_ looking like this!"

"Casey, I'll call and make you an appointment after school to dye it back," Nora assures her daughter. "But maybe you could wear a hat today!"

Casey scrunches up her pert nose, but stomps out of the room with one last glare at her stepbrother. Nora shoots George a pleading look and follows, and in the doorway, George folds his arms.

"Dad, come on, it was just…" Derek tries to laugh it off but trails off when he sees his dad isn't having it. He ducks his head between his knees and rubs a hand over the back of his neck. _Eh, well, still worth it._

"Get to school, Derek." George sighs. " _On time_ , and as soon as it's over you're going to come home and stay in this room until you show some remorse for your actions." He pauses. " _Genuine_ remorse."

 _Remorse_ , Derek scoffs as he ends up alone on the floor in his room. _Right._


	3. Chapter 3

**–** **3 –**

Of course, Derek _can't_ come home right after school because he has hockey practice. Even so, he still beats Casey home, because even though she went right after school, she has to spend a good several hours at the salon while the very sweet, very patient stylist tries to put Casey's natural color back into her hair. Even though she does manage to darken it, Casey stares sadly at her reflection in the mirror, and fingers a severely damaged strand the entire way home.

As soon as she steps through the front door, Nora ushers her into the kitchen, and with a stern look at Edwin and Lizzie leaning over the stairway banister, sends them away to the second floor.

Derek is already sitting at the island, eating a sandwich, and Casey gives him a withering glare and takes the stool as far away from him as possible. Nora sits down next to George and clasps her hands together as though in prayer before she says her piece in a careful tone.

" _ **WHAT!?**_ "

"We've decided," Nora repeats, "that it would be in the best interests of the whole family if the two of you…spent a week in each other's shoes, so to speak. By spending a week in each other's rooms."

Derek and Casey's aghast gazes fly to each other and back to their parents. " _ **WHAT!?**_ "

"It's decided," George agrees, placing his hands flat on the kitchen island in what's supposed to be either a set or a calming gesture, though neither Derek nor Casey could possibly feel calm now. "You two will switch rooms for one week in order to learn about each other and find some common ground."

Derek and Casey exchange a look; they stand on common ground already in agreeing this is the worst idea their parents have _ever_ had.

"You'll be able to go into your own rooms for essentials, such as changing clothes for school, but the time that you would normally spend in your own rooms, _including sleeping_ , Derek you will now spend in Casey's, and Casey you'll spend in Derek's. The only exception—" at this Derek opens his mouth, but Nora silences him with a look, "—will be if you two are in one of your rooms, _together_. Otherwise, you'll be with the family. And _not_ fighting."

"You expect me to sleep in _Derek's_ room?" Casey cries in horror. "In his _bed_!?" She gags. "Ugh, can't you just pitch me a tent in the backyard instead!?"

"You'll be fine, Casey," George assures. "The sheets can be changed first."

"Dad, you don't honestly think I'll be able to live in Casey's room! It's all…pink and girly and…and…"

"And you'll be fine too, Derek," Nora says. "So it's settled, and you two can start…" She looks at her watch, "now."

"But—"

"But—"

"No." She gestures toward the stairs. "Upstairs, both of you, and we'll see you at dinner."

With one resigned look at each other, Derek and Casey take off running, each jockeying to be the first upstairs and into his or her own room before the other can destroy it.

"Each other's bedrooms!" George yells for good measure. He turns to Nora. "Do you think any of us will survive this?"

"Well…no." She wrings her hands, biting her lip, and quickly pastes on an optimistic smile. "But I've already booked a hotel room for the rest of us, just in case!"


	4. Chapter 4

**–** **4 –**

In the middle of Derek's room, Casey stands in one spot. Very still, arms at her sides. Shallow breaths. Maybe, if she doesn't move or breathe in too deeply, she'll only risk _minimal_ contamination.

But she can't do that for an entire week.

"How the hell am I supposed to _survive_ this week!?"

In the middle of Casey's room, Derek stands in one spot. Very still, arms at his sides. Shallow breaths. Maybe, if he doesn't move or breathe in too deeply, he'll only risk _minimal_ contamination.

But he can't do that for an entire week.

"How the hell am I supposed to _survive_ this week!?"

 **A/N: Sorry guys that this isn't much of an update. More is forthcoming, I promise!**

 **I received a review from a guest, DieHard FanBoi, asking about my friend Nemo (N Hus) and she is alive and doing fine! I've been emailing back and forth with her, and she's been more active on Tumblr recently so if you'd like to get in touch with her then please contact her there! Her URL is the same. Bet she'd love to hear from you!**


	5. Chapter 5

**– 5 –**

 **Tuesday**

When the alarm clock goes off at 6:00 the next morning, Casey opens her eyes and screams.

"Der- _ek_ , what are you _doing_!?"

"Sleeping, Space Case," he mumbles, shoving a pillow into her face. "Shut…" He trails off into a snore.

She shoves him as hard as she can onto the floor.

"Oww!" He gives her a withering glare, rubbing the back of his head, his hair sticking up in all directions. "What the hell!?"

" _You_ tell me, Derek!" She points a finger at him accusingly. "What the hell are you doing sleeping in my bed!?"

He smirks. "Actually Case, _you're_ in _my_ bed."

The blaze behind her blue eyes dims as they widen, and she stares down at the patchwork blanket thrown over her lap, at a loss for words. Visibly she cringes, and his smirk grows. She draws in a deep breath but it comes shakily, and she tries another and another until she's starting to hyperventilate. Derek, by contrast, calmly gets off the floor and starts rooting around in his dresser for a clean shirt.

Casey throws herself back against the pillows in agony and just as quickly bolts up again because, even if the sheets _were_ changed before she went to bed last night, now they have _Derek_ all over them. How did he even—?

"How did you even get in the room!?" she squeals. "I locked the door!"

He shakes his head in mock pity. "Casey, Casey. Spacey. Don't you know there isn't a single room in this house that I can't pick the lock to?"

She's so stunned she doesn't even put up a fight when he beats her to the bathroom.

In her own room she carefully selects an outfit from her closet and drapes it over the back of her desk chair, observing distastefully the unmade bed. Derek apparently _did_ try to adhere to their parents' rules before coming to invade her comfort zone—already made fragile by her being forced to sleep in _his_ room. Ugh.

"Casey, Derek!" she hears Nora call up the stairs. "Are both of you up? _Not_ in your own rooms!"

Casey drops her head into her hands. Already this week is off to a rough start.

Resigned, she trudges downstairs in her pajamas and bypasses the cereal lineup on the kitchen island in favor of the coffeemaker. _At least it's fresh_ , she acquiesces to herself as she pours a large mug and breathes in the delicious aroma. "Thanks for the coffee, Mom."

"George made it." Nora cups her hands around her own mug and brings it to her lips, leaning her elbows on the island. "So, how did it go last night?"

Casey rolls her eyes in response. "Are you _sure_ I can't sleep in a tent?"

Her mother responds with an apologetic smile.

Derek comes bounding down the stairs in record time, showered and shaved and dressed in clean clothes; the way he beelines for the front door makes it very clear he hoped to escape the house alone before the parental units caught him, but Nora's voice freezes him with his hand halfway to the knob: "Derek, where do you think you're going?"

He turns around slowly. "Uh. Early study group meeting before school?"

Nora cocks an eyebrow and folds her arms over her chest, and it's Casey's turn to smirk.

"Not without Casey, you're not."

"Man." His backpack slips off his shoulder as he thuds down the couple of steps, and drops into his recliner. "Fine." He picks up the TV remote. "Take your time, Spacey!"

 _Not a chance._

* * *

The day at Thompson High flies by, even for Derek who usually spends the last class periods with his eyes fixed on the ticking clock. Today ever second creeping closer to the final bell ticks a painful reminder that Casey and Derek will no longer be able to escape each other once they leave the campus. When the bell does trill, however, Derek feels a small thrill of relief, as two hours of hockey practice will let him work out some of his frustration with this arrangement. For Casey's part, she sighs, tugs on a jacket, and pulls every textbook out of her locker on her way to the ice rink to wait for him.

"Dude, what's Casey doing here?" Sam asks, clapping Derek on the shoulder as they hit the ice.

"Dad and Nora are forcing us to spend the week together so that we might 'get along better.'" His gloves make it difficult to add the air quotes, but Derek's expression of disgust gets the point across just as well. Sam grins, knowing that however the week ends, it will be a struggle.

Derek grimaces and slaps the puck, sending it flying into the glass.

* * *

"Here, Spacey." Derek drops the car keys onto the essay she's writing, and drops heavily onto the bleacher bench beside her.

"What am I supposed to do with these?"

"Drive me home."

"Where's the real Derek, and can you not return him, please?" Casey smiles and closes her hand around the keys before he changes his mind.

Derek rolls his eyes exaggeratedly. "Look, I'm exhausted and sore, and since we already have to go home together, I might as well take advantage. Carry my hockey bag too, will you?"

"Um, no." She shoves her books into her bag and stands up. "But I will drive."

She steps over his splayed out legs and marches down the steps, heading outside into the warmer air, and Derek drags himself up and follows.

The family is sitting down to dinner whenever they come in the front door, and, pointedly, Casey's usual chair beside Lizzie is now occupied by Edwin. She and Derek look at each other and then, resigned, take the pair of empty chairs next to each other without bothering to protest.

"So," Nora tries pleasantly, "how was school?"

"Great," Derek supplies, surprising everyone. "I finally got away from Head Case."

Casey moves to stab him with her fork but he pulls his wrist away, and knocks over Marti's milk glass.

"Derek!" "Derek!" "Smerek!"

Casey just smiles.

* * *

"'Sup, Case!" Derek barges into his own room and flops onto the bed, sending her French homework flying.

"Der- _ek_! Can you not!?" She smooths out the crumpled papers and tucks them into her book.

"Can you not?" He yawns. "I'm ready to go to bed."

"Well, then, leave." She points toward the door. "You're not sleeping in here."

"It's my room, Case." He smirks with the air of somebody who already knows he's going to get his way.

She closes her eyes and pinches the bridge of her nose. "Okay. Let me rephrase. You're not sleeping in here, _with me_ , _for the rest of this week_."

"What if you sleep on the floor?" he counters, and she looks at him like he's grown a third ear where his nose should be.

"No! If I'm being subjected to this torture already, I'm not _also_ sleeping on your filthy floor!" She pauses, and adds quietly, "Besides, your bed is softer than mine."

"So," he raises his eyebrows, "what I'm getting from this is, you like sleeping in my bed."

She rolls her eyes.

His smirk widens. "You know, Case, if you really wanted to sleep in my bed, all you had to do was ask."

"You disgust me."

He cracks up.

Stubbornly, Casey pulls back the bedcovers and plops down. Derek does the same.

"Look, Spacey, we could always just _share_ the bed."

She crinkles her eyebrows in confusion. "I thought the great Derek Venturi doesn't share."

"Yeah, I don't, but I'm not sleeping in your bed, and I'm not sleeping on the floor, and I know if I shove you onto the floor you'll just go tattling to Dad and Nora, so." He turns up his palms in a show of surrender.

She throws a pillow at his face. "I do _not_ tattle!"

He shrugs and slides down underneath the covers, getting comfy. Casey sighs, defeated, and turns off the light.

"Try not to touch me, Derek."

"Don't breathe on me, Case." A pause. "And don't wake me up at the ass-crack of dawn, either."

"Whatever, Derek."

"And don't go through my stuff, either."

"Good _night_ , Derek."

A longer pause. "G'night, Space Case."


	6. Chapter 6

**– 6 –**

 **Wednesday**

The alarm goes off half an hour before 6:00 the morning, and Casey sits up, yawning and rubbing her eyes. Next to her, Derek groans but sits up too, and the sight of his not wearing a shirt startles Casey into full alertness.

"Derek! Why the hell aren't you dressed!?"

"I got hot." He stretches, toned muscles flexing.

"Are you… _Please_ tell me you're still…?"

"Yes, Casey, I'm wearing boxers."

" _Boxers!?_ You're not even wearing pants!?" She buries her face in her hands. " _Oh, my God._ "

"Why are we even awake at…?" Derek looks at the clock and curses. "Case, no reasonable human being gets up at 5:30 in the morning! What's wrong with you!?"

"I need time to get ready!" she defends. "Especially now that I have to leave when you do. God, I cannot _wait_ for this week to end."

"You're tellin' me," he grumbles. "My bed's not big enough for both of us."

"Well, considering you're supposed to be sleeping in _my_ bed…!"

This morning, he shoves her onto the floor and she beats him to the bathroom.

* * *

The school day, too, passes in much the same way as the first, except in Spanish, Derek cheats off Casey's quiz. She retaliates by waiting until he's handed his in to change all of her answers to the correct ones. But in Health and Life Studies—plainly referred to as Sex Ed by every student except Casey—they are partnered up for the baby project, and Casey finds herself wondering whether karma really does come back around _that_ fast.

"Come on, Casey, how bad can it be?" Emily tries to reassure her as they're putting books in their shared locker at the end of the day. "You're already spending all this time together anyway. What's that saying—two birds with one stone?"

"How about two stones," Casey counters, fighting to shift the baby carrier to her other arm, "that I can throw at his head?"

Emily smiles. "You'd miss."

" _Thanks_ , Em."

"I'll text you tonight, okay? If my parents don't follow through with that 'family dinner' thing." Emily shifts her bag higher on her shoulder. "I'll see you tomorrow, Case."

"Bye, Em. See you." Casey lingers at the locker, while Emily starts walking away.

Emily smirks to herself. "The _real_ question is, would she miss on accident, or on purpose?"

"Spacey! Just the Head Case I wanted to see." Derek pops up behind her and drapes an arm over her shoulders. "So, this project—you're going to make sure we ace it, right?"

"If by 'make sure we ace it' you mean 'raise this fake baby by myself until we turn it in Friday,' no." Casey uses the carrier to push him off of her and nudges the locker door shut with her foot. "Do you have hockey practice or can we just go?"

"I _always_ have practice, Case. What, you don't have my schedule tabbed and color-coded right next to yours?"

"Then give me your jacket so I don't freeze while you're on the ice."

"What's wrong with your jacket?" Derek demands, already shrugging the signature leather jacket off his shoulders.

She rolls her eyes. "I'm going to have to wrap it around this thing."

He raises an eyebrow in question.

"It's sensitive to the environment."

As if on cue, the baby doll begins to wail, and Casey sighs. "See?"

"Great." Derek sighs, too. "Why am I in this class again?"

"It's required." She pulls the doll out of the carrier and bounces it gently in one arm, and shoves the carrier into Derek's arms. "Here. Carry this for me, will you?"

Before he can argue, she struts off toward the ice rink, determined not to let him weasel a way out of this project—she was already being punished one time over.

* * *

In the evening, Derek spins around and around in Casey's desk chair while she lounges on the bed, looking over the project paperwork. She glances up at him and scowls. "Stop that, Derek, you're going to make her dizzy."

"Dolls don't get dizzy, Case. And how do you know it's a her?"

"Because unlike _you_ , I changed the last four diapers." Casey holds up the packet. "Plus, it says so right here."

The doll begins to cry, a soft wail that escalates into a loud screeching, and Derek fumbles the baby and throws it at Casey. It thumps off the bed onto the floor, and Casey quickly reaches to pick it up and cradle it. "Der- _ek_! You can't do that; there are sensors that record how _we_ respond to everything!" She rocks the baby back and forth until it quiets. "Shhhh…" She reaches for the packet and throws it at Derek's head. "If you're not going to parent the child, you can at least read those instructions to me."

"Fine." He skims down the page. "Okay, we have to name it. Easy! We'll name it after you."

Casey gives him an incredulous look. "Are you serious?"

"Sure, Klutzilla!"

She scowls. "No way, _Dereka_."

He mirrors her expression perfectly. "Fine, how about we name it after Marti?"

"Martina Elizabeth, then." Casey nods toward the paper. "Write it down. What else?"

"Okay, it says we get to choose our careers, and then we have to go online to find out how much those careers would make, and use that to plan out a life plan for us and our…" He cringes, swallows. "Baby."

Casey feels her cheeks warm, and she quickly bounces the silent doll.

" _Casey! Derek!_ Dinner's ready!"

"Thank God." Derek tosses the paperwork aside. Casey gets up to head out of the room, and Derek stares at her. "You're not bringing that, are you?"

"We _have_ to, Derek," she reminds him. "Here. You can carry Martina." She thrusts the doll into his arms. " _Gently._ _And_ you're changing the after-dinner diaper, because that doll also records how much work _you_ put into this project."

He clenches his teeth and looks down at the doll in his arms, fighting the urge to throw it over the staircase banister and be done with the whole mess. The doll opens startlingly lifelike blue eyes, not totally unlike Smarti's, and he swears the thing is trying to smile at him.

He's halfway down the staircase when the realization hits him: they're not totally unlike _Casey's_ blue eyes, either.

 _Shit._

* * *

Nora serves the meatloaf to a silent dinner table; everyone is staring curiously at the baby doll Derek is cradling uncomfortably. Casey slides into the seat next to him, smirking.

George looks back and forth between them. "Something we need to know?"

"Did Derek and Casey have a baby?" Marti asks innocently. George chokes on his drink while Nora smiles uncertainly, Edwin and Lizzie exchange a knowing smirk, and Derek and Casey turn red and unconsciously shift as far away from each other as possible while remaining in their chairs. The doll in Derek's arms gurgles placidly.

"No, sweetheart," Nora says to Marti, spooning mashed potatoes onto her stepdaughter's plate. "It's just a doll. For an assignment, right?"

"Yeah. Health and Life Studies," Casey confirms.

"Sex Ed," Edwin snickers, and George covers Marti's ears. She fights his hands away.

"We're supposed to take care of this baby until we turn her back in on Friday," Casey explains.

"Her?" Lizzie asks. "It's a girl?"

"How can you tell?" Marti questions, and more looks are exchanged.

"Yes, it's a girl. Her name is Martina Elizabeth."

All heads turn toward Derek.

"What?" He bounces the doll, somewhat defensively. "Just wanted to be done with that part of the conversation."

"Well, that's great," Nora enthuses. "This should certainly help both of you with teamwork and having to get along, right?"

"What a coincidence for it to be this week," Lizzie remarks, spooning peas around on her plate. "Like, what are the chances?"

Casey forces a smile. "Yeah. Like Emily said, two birds and one stone."

Or two stones she could throw at the universe. Or, failing that, at Derek. (Always at Derek. After rescuing the doll, for the sake of the assignment, of course.)

* * *

Derek sleeps like the dead, so Casey doesn't even bother asking if he'll take the baby for the night. Instead, once he's given her an evening bottle, changed her diaper, and dressed her in some of Marti's doll pajamas, he hands Martina Elizabeth off to Casey and closes himself in her bedroom, privately resolved to take this opportunity to hunt for her elusive diary.

Casey, for her part, is unsure about the opportunity that seems to have just landed in her lap. Or on Derek's bed, rather, as without the responsibility of Martina Elizabeth, she probably would not be afforded this respite from Derek's presence…even though she's somewhat uncomfortable to think about what he could be doing in her room without supervision. Probably she should've rescued her diary, but it's so well hidden he won't find it. _And even if he does_ , she muses, _knowing Derek there's no way he'll believe what's in it, anyway, and he'll convince himself that it's a decoy, and will instead look for a second one that does not exist._ It's sort of like a diabolical form of reverse psychology, but it could work.

She plops down in the middle of his bed and looks at the doll. Martina Elizabeth is quiet, but only just for now, as Casey knows the doll has been programmed to wail at least every few hours, just like a real newborn. She wads up a throw blanket and packs it into the baby carrier as a makeshift bed, and gently placed the doll inside. Then she looks around the room.

With all the time she's been spending in here, and all the months she's lived in the room on the other side of the wall, she's never given much thought or attention to this space that's so sacred to Derek he wouldn't even consider giving it up for the much larger basement bedroom, which would have afforded him easier access to the kitchen and unlimited privacy. Casey shivers. It's a strange feeling now, to be alone in Derek's room, among Derek's things, and especially with Derek's consent. (Reluctantly as it may have been given.)

Focusing on the space now, Casey realizes that it's actually kind of nice (particularly with her additions of clean sheets and air freshener). The dark paint on the walls and the red furniture make the large space feel cozy, and the posters tacked up everywhere add pops of brightening color. The patchwork blanket on the bed, velvet squares of navy, plum, olive and cream, seems very Derek but is neutral enough to not be hideous, and is incredibly soft under Casey's hands. So is his entire bed, actually—she wasn't just bitching when she argued that his _is_ more comfortable than hers.

Curiously, she moves to examine the bookshelf, tilting her head to the side to read the titles. They don't appear to be organized in any particular way—that would be asking too much of her slacker stepbrother—but the fact that they are on the shelf at all—or even the fact that Derek Venturi _owns_ books—is surprising enough, and pleasantly so. Some look like they were assigned reading for school at one point or another: _The Great Gatsby_ , _Lord of the Flies_ , and she realizes this last one must be where he cleverly derived "Lord of the Lies" from. Other books that probably wouldn't have been assigned in class are more worn, as if he's flipped through them several times: _Stormbreaker_ , _The Outsiders_ , even _Treasure Island_. Casey traces a fingertip over the books' spines, trying to grasp the truth she's just learned: Derek _reads_.

"What _else_ does Derek do?" She glances around the rest of the room. His guitar is propped up on a stand in the corner. His computer hums quietly on the desk. His closet door is ajar, the space inside dark and silent, like the space under his bed.

She wanders over to the closet and pulls the door the rest of the way open. It's a mess, just like his room was before she was forced to move into it: clothes tossed haphazardly over discarded shoes, hockey gear, and textbooks that look like they've never been opened. Nothing that's surprising—or incriminating. _Damn._

What about under the bed? Casey kneels on the rug and peers hesitantly underneath the bed, expecting to find pizza boxes, roaches, issues of _Playboy_ , but is met only with dust bunnies and a few stray articles of clothing. A hoodie, it seems, a couple of pairs of boxer shorts ( _ugh!_ )and… Her eyes widen. _Is that a bra?_ She reaches underneath and can _just_ wrap her fingers around the silky material; she pulls it out, expecting something discarded casually by Kendra, or perhaps passionately by Sally? But her mouth drops open in recognition.

"This is the bra that I was looking for ages ago! _**DER**_ —" and his name dies on her lips as she turns the garment over and over in her hands, suddenly wondering when exactly had this one gone missing, and how the hell did it turn up in _Derek's_ room? _Underneath Derek's bed?_

Martina Elizabeth screeches suddenly, jerking Casey out of her shock, and she quickly picks up the doll with one arm and rocks her back and forth, all the while fingering the lace detail on the bra in her other hand. Absently she shushes the baby, thoughts preoccupied with Derek and what she should do.

 _Nothing._ That's it—she shouldn't do anything. Not yet.

She shoves the bra back underneath his bed. For now, he never has to know she knows.

* * *

In the room next door, Derek is spinning around and around in Casey's desk chair again, but this time in frustration.

"Where did she hide it?" he mutters to himself, annoyed that he hasn't been able to locate the diary he _knows_ Casey has hidden somewhere in this room. It has to be in her room, because there's too great a risk of somebody else finding it if she hides it somewhere in the house, and there's not a chance in hell she'd take it to school, or hide it in the Prince. No, it _has_ to be here.

"If I were a 17-year-old girl…" Immediately he shudders and shakes the thought from his head. "No. No, I do _not_ want to know what it's like to be Keener Klutzilla." He flops down on her bed and blows out a sigh.

It's quiet upstairs, at the moment. It's quiet next door, and he wonders what Casey's doing in his room. Probably ransacking it, looking for blackmail material… Good thing he returned…

" _Shit!_ " Derek bolts upright, brown eyes wide with horror, and rakes a frantic hand through his hair. "Shit, shit, shit…" He yanks open the drawers of Casey's dresser until he finds the one filled with silky, satin, lacy bras and panties in matching candy colors. _Is it…? Did I forget…?_

How long ago did he sneak that particular bra out of her drawer? Did she even notice it was missing?

It's not in the drawer now, which means that either he forgot to put it back, or…she's wearing it now. His throat closes.

"Okay, Derek, calm down… She never said anything. She would've said something. She would've ripped your name in half like she always does, and probably tried to murder you, or moved to New York to live with her dad and get as far away from her annoying, scheming, disgusting stepbrother as possible…" He shuts up as soon as he realizes he's rambling.

 _But that must be it—Casey has no idea. Whether he put it back or whether he forgot, it doesn't matter, because she can't possibly know, because he'd know by now if she does._ He sighs deeply, a colossal weight melting from his shoulders.

Next door, he hears the muted electronic screech of their Health and Life Studies assignment, and he grins like the Cheshire Cat. He's safe, and she's got her hands full, and he'll find that diary tomorrow. For tonight, he's going to sleep like a baby.

Or, actually, a hell of a lot better than that damn doll.


	7. Chapter 7

**– 7 –**

 **Thursday**

When her alarm goes off at 5:30, Casey's so exhausted she almost sleeps through it. Twice she hits SNOOZE; only when Martina Elizabeth begins to wail does she drag herself from Derek's bed, all the while glaring at the wall between their bedrooms—the wall on the other side of which, she knows, he slumbers peacefully.

Carrying the crying doll, Casey slips out of Derek's room and over to her own, fully prepared to turn on the light, wake him up with a pillow to the face, and force him to take care of the baby while she enjoys a luxurious hot shower and a cup of strong coffee, but she hesitates in the doorway. Derek sleeps with one arm casually flung over the pillow beneath his head, his bare chest rising and falling with each gentle breath in the silver moonbeams filtering through Casey's window. He's not smirking or scowling, and Casey realizes she's never seen him look so peaceful and vulnerable at once. Almost, she suddenly doesn't want to wake him.

Martina Elizabeth, though, doesn't care—as evidenced by the ear-splitting screech she emits, and Casey fumbles and drops the doll, startled. Derek bolts upright in bed, dark eyes blinking to adjust to the moonlight, and his gaze settles on the doorway. "Case?"

"Sorry." She quickly shuts the door before anybody else can be woken up, and she moves to pick up the doll but trips over yesterday's jeans that Derek left on the floor and she goes sprawling, long dark hair over long legs, across the carpet.

"Jesus, Klutzilla, you okay?" Derek throws back the blankets and gets out of bed, reaching her just as she gets her bearings, and strong hands wrap around her arms and lift her up. He guides her to sit on the foot of her bed, and turns on the lamp on her desk. "Wow. You look like hell, Spacey."

She gives him a dirty look. "Thanks a lot, jerk." She sighs, rubbing a hand over tired blue eyes. "I didn't get any sleep because of that damn doll. What day is it? Is it Friday?"

"Don't you usually study all night, anyway? It's Thursday, Space Case." A half-smile that's almost affectionate tugs at the corner of his mouth.

Her face falls in defeat, and Martina Elizabeth shrieks again. Casey startles, nerves shot, nearly falling off the end of the bed while reaching for the carrier, and Derek just manages to catch her around the waist and haul her upright again. "Okay, Case… Since there's no chance you're going to let me go back to sleep, here's what's gonna happen. You're going to go take a shower and get ready for school, and I'll go downstairs and make us both coffee. Okay?"

"What about…?" Her head slumps onto his shoulder and her voice trails away. She waves a hand listlessly in the direction of the crying baby doll.

"I got her. Okay?"

"S'oh… Kay…" Casey nods off and her head falling forward yanks her into momentary alertness. "What!?"

Derek bites down on the inside of his cheek. "Okay, Case… C'mere." Gently he slides one arm underneath her knees and wraps his other around her back, and he picks her up, cradling her slight weight against his chest. He carries her into the bathroom and places her in the tub, sitting, before he draws the curtain and turns on the water. Cold.

" _DER-_ _ **EK**_ _!_ "

All at once, George and Nora, Edwin, Lizzie, and Marti all open their eyes, glance around for the time, and pull the bedcovers more tightly up to their chins. Derek and Casey can work out their own problems; wasn't that the point of the punishment, after all?

While Casey is in the bathroom, Derek quietly takes care of the baby doll, giving Martina Elizabeth a new diaper, a bottle, burps, and eventually another new diaper, at which point he carries her downstairs with him to make the coffee he promised. Meanwhile hoping Casey isn't so pissed off at him for the cold shower that she'll throw hot coffee in his face.

It's 6:15 when Casey finally comes quietly down the stairs, fresh and beautiful in a pair of leggings, an oversized sweater and ballet flats. She stops in the kitchen doorway, watching as Derek cradles their assignment in one arm while pouring coffee into two mugs with his other hand. Carefully he picks up one in each hand and turns around to place them on the island, and he glances up, locking eyes with her.

She drops onto a barstool and reaches for the closest mug, wrapping manicured hands around the warm ceramic. Lifting it to her lips, she takes a grateful sip, closing her eyes as the heat rushes into her.

"You're not even going to ask whether I poisoned it?" Derek raises an eyebrow.

She takes another sip and sets it down. "I watched you pour the coffee, genius."

"So? I could've mixed rat poison with sugar in the bottom of your cup, and you never would've known." He shakes his head, glancing at the doll in his arms. "It's a good thing I need you to do this assignment for me, otherwise you'd be dying on the floor right now."

"I'm sure I would." She rolls her eyes and reaches for the doll. "Here, I'll take her."

"It's fine, Case."

She freezes with her hands in mid-air. "What?"

"I said it's fine." He shrugs, not meeting her eyes. "She's being quiet now. And you didn't get any sleep."

She takes another sip of coffee, staring at the tiled countertop. "Thanks, Derek."

He gulps his coffee, wincing as it burns down his throat. "Don't mention it."

* * *

After school, after hockey practice, Derek spins around and around in his own desk chair while Casey sits cross-legged on the bed, Martina Elizabeth in her lap and their assignment details spread out in front of her.

"Der- _ek_ , will you help me do this assignment, please!?" Casey swipes her hair away from her face.

"I am helping." He smirks. "I'm being quiet and staying out of your way."

 _Well…can't argue with that._

"Okay, the first thing we have to do is decide what careers we're going to have, but—"

"Professional hockey god," Derek says immediately.

"— _but_ ," she says testily, annoyed with his interrupting, "they have to be realistic."

"Fine." He stops spinning. "Professional hockey _player_."

"Derek, that's hardly realis—"

"Please, Case, you wound me." He clutches his chest. "I'm _really good_ at hockey. Colleges are already scouting me; Coach said so."

"Fine." She shakes her head, knowing that that's another thing she can't argue with: Derek _is_ very talented on the ice. "Professional hockey player." She writes it down. "I need you to go online and find out how much you'll make per year doing that."

He logs onto his computer, and after a few minutes, she's able to write down the figure he offers.

"Now, what do I want to do…" She taps the pen against the paper thoughtfully. "Hmmm."

"What are you talking about? Obviously I'm going to make way more than enough to support us."

"I can't just _not_ do anything, Derek! I'd go stir-crazy."

"You're already crazy," he reminds her, and she glares daggers at him.

"Probably too crazy for reliable employment," he continues, a wicked gleam in his dark eyes. "No, you'd be best staying at home with the kids, away from the public, washing my hockey gear and cooking meals…"

"Kid _s_!?" She raises both eyebrows, blue eyes wide, but Derek is distracted now by the unbidden mental image of Casey wearing an apron and…little else.

"I'm going to write down 'dance instructor.' Look up the salary for me, Derek."

"But I thought you had to be _good_ at dance in order to teach it?"

Without thinking, Casey picks up the closest object with any weight to it and hurls it at Derek's head; for just a fraction of a second his eyes widen in horror before he reaches up and snatches Martina Elizabeth from the air. " _Casey!_ "

The pen slips from her fingers as she claps both hands over mouth, eyes wider still. "Omigodomigod _omigod_ is she okay!?"

The doll begins to wail, and frantically Derek rocks it back and forth. "Shhh, it's okay… Mommy and Daddy are gonna get a divorce and I'll sue for custody since she can't be trusted…"

Casey's not sure whether to gape or smirk. Derek gets up from the desk chair and coldly glares at her as he carries the doll to the door. "Finish the assignment, will you, and _I'll_ watch the baby tonight since you nearly murdered her!"

He shuts the door a little too hard, and she can only stare at the wood, confused about whether to feel uncomfortable or incredulous at his behavior. "It's…just a _doll_ …"

* * *

Once he's in Casey's room with the door shut, Derek looks down at the doll in his arms with dismay. How did he end up here, stuck with this baby simulator for the night—and basically by his own choice? More importantly, what should it matter to him how Casey treats their baby? It's not even a baby. It's a doll.

He tosses Martina Elizabeth on the bed and begins rummaging around for the diary that eluded him last night.

After a solid seven minutes, he gives up and flops down on the bed beside Martina Elizabeth. _Of course_ Casey took great pains to hide her diary after the hair bleaching incident. He sighs through his nose, and thinks about how she looked with blonde hair that morning. Not _terrible_ , considering blondes are usually what he goes for, but it didn't look as pretty as her natural rich chestnut sheen. Plus he damaged her hair in the process…and he did feel a _little_ sorry for that. Not that he would ever admit that out loud.

"Der- _ **ek**_ , you read my diary!?" Casey had screeched at him.

The truth is, he _hadn't_ read her diary. He didn't know if it said anything about Max when he made that comment, though now he has a pretty good idea that it does. _She's_ still _into that jerk?_

He springs up again with renewed energy and begins tearing pillows off her bed and flinging them to the floor, hoping to find a tiny pink book somewhere under all the extraneous fluff that girls think they have to have.

 _Seriously, who needs six sequined pillows? She doesn't even sleep on those!_

Alas, no diary.

He's pulling pillows off the floor to replace them, when a small piece of paper flutters out from one of the decorate pillow cases and floats through the air to rest at his feet. He crouches down and picks it up, eyes widening.

It's a photo of the two of them. With him wearing a white blazer over a black button-down, and Casey modeling a perfect pink princess dress. Her perfect pink princess… _prom_ dress.

It's a picture from the night he took her to prom.

 _Delivered_ her to prom, actually…to Max, while Kendra was his own date.

None of that matters now, though, because he's curious as to what in the world _this_ picture is doing _inside Casey's pillowcase_. And why is it creased and a tiny bit faded, like it's been handled over and over and over?

He goes to the door but stops with his hand millimeters above the handle. _Wait. Not yet._

Instead, Derek shoves the picture into his pocket. _Now, the diary…_

He surveys the room. Except for the mess he's made, it looks like it always does. Bright and colorful and neat as a pin, with her clothes put away inside the dresser and closet, and her homework and textbooks, each covered in protective brown paper, meticulously organized and stacked on her desk.

 _The textbooks._ He narrows his eyes and dives across the room. She knows he's allergic to academic material, and therefore the textbooks would be the last place she would expect him to be willing to go near… He flips open the cover of each book to see what they are.

Math. Science. History. English Language. English Literature. History. French.

 _Wait—! Two_ history books?

Shoving the others aside, Derek places the two history books side by side and pages through them, until…

There it is. A small, pink velvet book with a lock, _inside_ a _hollowed-out textbook_.

Derek pauses, feelings of pride and admiration blossoming at her ingenuity. It's so well thought out, and yet still so very _Casey_.

 _Impressive._

Carefully he picks the lock, and sits down on her bed to read.

* * *

On the other side of their shared wall, Casey is working on the rest of their Health and Life Studies assignment, using Derek's computer because her own is locked inside her room with him, and she, the _good_ child, does not know how to pick the door lock. Not that she would if she did. (Would she?)

More than that, though, she doesn't feel like expending the energy it would take to get Derek to open the door, particularly after his bizarre reaction to her throwing Martina Elizabeth at him. It's just a doll, after all, and a school assignment—neither of which he's ever shown any regard for in the past. _Why now?_ Not that she wants to expend the energy to mull over that, either; besides, she has work to do.

She fills in a few more blanks on their worksheet, using information she finds online, and then because one of the assignment stipulations is to include a couple of legitimate sources to back up the answers for things like salary, she saves a couple of web pages to his desktop. When she minimizes the Internet browser, she quickly locates the saved files, right underneath an inconspicuous folder named "CV."

 _Curriculum Vitae?_ Casey scoffs. Derek wouldn't even know what one was, let alone have an entire folder dedicated to one. He probably can't even spell "curriculum vitae." She clicks on it.

* * *

Derek thumps Casey's diary shut and stares numbly at the cover. He's not sure whether to believe anything he's read or not—maybe it's a decoy diary. Would Casey have one of those? He wouldn't put it past her…but if this one _is_ a decoy, why did she take such great pains to hollow out a textbook in order to hide it?

He tosses it to the floor and flops backward onto her thousand sequined pillows and stares at the white ceiling. If he knows Casey—and he _thought_ he does—none of what he read can possibly be true. Not one word.

 _But…_ He pulls the picture he found out of his pocket.

If it _is_ true… "That would certainly explain this."

* * *

Casey exits out of Derek's "CV" folder and stares at his desktop background. She's not sure whether to believe anything she's seen or not—maybe it's a practical joke. That _is_ something Derek would do.

She quickly prints out the resources she needs for their assignment and staples them to the paper, and tucks it away in a folder. The written part of the project is done, and Derek is taking care of the doll for the night and they can turn everything in during class tomorrow. Then they just have to get through the rest of the week in each other's rooms, and things will return to the way they've always been.

 _But…_ She reopens Derek's folder and stares. Knowing him, it _has_ to be a prank, but…

"If it's not…" Her gaze falls to the floor next to his bed, thinking about what's hidden underneath. "I guess it would explain _that_."


	8. Chapter 8

**Friday**

 **A/N: I made a couple of small changes regarding the "CV" to the previous chapter that will affect the story later on. Please skim over the last chapter to see what's different!**

On Friday morning, for the first time in her academic career, Casey does not have an alarm set. Instead, however, she's quite literally shaken out of a pleasantly dreamless sleep by Derek's insistently shaking her shoulder.

"Mmph— _what_ , Derek?" she mumbles, irritably sitting up in his bed and rubbing sleep from her eyes. "What time is it?"

"Time to get up, Case," he whispers, kneeling by the bedside, Martina Elizabeth in his arms. "She's hungry."

Casey gives him a _look_ , but takes the doll and climbs out of bed. "And you couldn't take care of this? It's not like I'm breastfeeding."

Derek stops in his tracks so that Casey walks into him, and they both blush brightly in the darkened hallway.

"I'll get the bottle, you make the coffee," she mumbles, hustling past him down the staircase.

In the kitchen, Derek slides a mug of coffee in front of Casey while she perches on a barstool at the island, the tiny nip of the little plastic bottle in the doll's mouth. She moves to hold the bottle up with the same arm she's holding the doll, and curls her free hand around the mug handle. "Thanks."

"Yeah."

He sits down, too, perching awkwardly so that he has to readjust his feet, and he knocks his coffee cup to the side in the small scuffle, sloshing liquid over the countertop.

He waits, but "Der- _ek_!" never comes, so he reaches for a towel and just mops up his mess, wondering if she even noticed.

"Should've made you do it, Head Case," he muses. "Cleaning is women's work."

Nothing, and he _knows_ she must have heard him. What he wants to know now is, why isn't Casey arguing with him about feminism?

"Spacey."

Nope.

" _Casey!_ " He waves a hand in front of her face, and blue eyes blink up at him placidly.

"What?"

"Didn't you hear anything I said?"

"I heard."

"Why aren't you saying anything?"

" _Be…cause…_ I don't have anything to say." She drinks the last of her coffee and slides the mug across the counter to him, and obligingly he gets up and turns to the coffeepot to refill her cup. But when he turns back around, she's gone.

* * *

Derek corners Casey at her locker before their Health and Life Studies class, and takes the baby carrier she immediately hands over. He waits, but she doesn't say anything, and remains focused on organizing her textbooks.

"Spacey, why're you avoiding me?"

She rolls her blue eyes in exasperation but still doesn't look at him. "I'm _always_ avoiding you, Derek."

Abruptly Derek closes his mouth—even he can't argue with her about that. "But you're doing it even _more_ than usual, and I wanna know why."

"Maybe it's because I have to spend every waking second—and every sleeping second, come to think of it—around you at home this week," Casey says drily. She closes the locker door and pushes Derek down the hall. "Now, if you make us late for class, I will remove your hockey cards from their plastic and let Marti use them to make pictures and potions."

"I know you're, like, the queen of annoying punctuality," Derek protests as Casey shoves him in front of her toward their classroom, and she raises her eyebrows, impressed at his use of a vocabulary word, "but this is ridiculous, even for you. I wasn't going to make us late."

"Good," she says, focused on the doll, "because I can't wait to turn that thing back in." She walks ahead of him into the classroom, and Derek frowns over the baby carrier.

They end up with an 89 out of 100 points on their assignment, because, as Casey warned Derek, the teacher is able to determine exactly how they cared for their baby—though, of course, Casey's careless flinging of the doll at Derek's head does not go unnoticed. The worksheet component is handed back with comments: _"I might have expected better from you, Casey, but I'm relieved to know that, working together, you and Derek have the capability of keeping a child alive, and not completely ill-cared for!"_ Casey's face flames as she reads the paper and she quickly moves to stuff it into her bag, when Derek, who hasn't gotten to see, snatches it from her hand and skims it. He hands it back with a smirk and leans back in his chair, hands folded behind his head, and she tries to crawl underneath her desk.

* * *

At the dinner table that evening, Nora asks how Derek and Casey did on their assignment. Casey, still seated next to Derek, crawls underneath the table.

"Casey?" Lizzie knits her eyebrows in confusion over her sister's behavior.

"I, um, lost my contact!" Casey calls.

"But you don't wear—"

" _We_ did very well," Derek speaks over Lizzie, in his most important tone of voice. "Mrs. DeMaris wrote that we—" he raised the pitch of his voice and used his fingers to create air quotes, "'have the capability of keeping a child alive, and not completely ill-cared for!'" He shrugs then and returns his focus to his mashed potatoes, while Casey, with the truth now out, emerges from the floor red-faced and trying to hide behind her hair.

George and Nora gaze pensively at their two older children, until George finally says, "Well, it's good to know that you two _are_ capable of getting along."

"So we can stop being punished now?" Derek asks, a gleam of hope in his eyes.

George and Nora look at each other and burst into laughter.

Casey looks at Derek as if to say, _Did you honestly think that would work?_

"Was worth a shot," he mumbles.

After dinner they run up the stairs, jostling each other to be in the lead, and then go into their separate rooms and lock the doors, because it's annoying to be around the family when everybody is paying such close attention to how they're acting, and it's awkward to be around each other.

Derek flops down on Casey's bed with a hockey magazine, and Casey settles into Derek's computer chair to work on homework.

Eventually, he reaches under her pillow to retrieve the diary he stashed there for easy access, and opens it to read. Casey keeps meticulous records of her life, but the last entry is from Monday, after she woke up to bleached blonde hair.

 _Derek put bleach in my leave-in conditioner. It must have only been a small amount because I didn't notice any burning or anything, but it was still more than enough to severely damage my hair, and I could kill him for it. I could kill him for a lot of things, and maybe one day I finally will. Even with somebody you love, there has to be a breaking point._

 _I still feel weird writing that down, but I've finally found a hiding place so good that even Derek in all his evil genius won't find it. After I woke him up, screaming, he made some comment about Max liking blondes. I screamed at him for reading my diary, even though, obviously, there's nothing about Max and hasn't been for months. But let Derek think there is. It's much safer this way._

He flips back several entries, just to confirm (again) that there hasn't been anything written about Max in months. There hasn't, but there is page after page about _him_. Mostly ranting, naturally. He nods to himself; isn't that the point of his pranks, after all? To keep Casey's attention on him.

He flips back too far, and stumbles across an entry that does gush over the quarterback, and Derek narrows his eyes at the loopy, girly script. As he stares at that page, though, a couple of phrases leap out at him: _Derek did… Stupid Derek… I don't think Derek…_ and his jealousy calms; even then, Casey was focused—perhaps too much, given what the entry is _supposed_ to be about—on him.

He turns back to Monday's entry and pauses over the pages. Then he pulls the printed photo from his pocket, tucks it into the seam of the book, and closes up the diary.

On the other side of the wall, eventually, Casey mouses over to Derek's "CV" folder, and double-clicks to open it. She knew Derek to be meticulous in his pranking, but not so meticulous in his…well, _observations_ , she supposes. How else should she describe the picture after picture that are contained in this folder, tiny thumbnails that all appear to have something to do, somehow, with _her_?

She double-clicks on one to make it bigger, and up comes a photo of Casey, lounging on the couch in sweats and a messy bun, a book balanced against her knees. From the angle of the photo, she surmises it was taken from the staircase, looking down into the living room.

She opens another: a shot of neatly printed index cards spread out across the kitchen table. They look like the notes she uses to quiz herself for exams, and they're upside down; upon closer inspection, she realizes they are her notes, and at the end of the shot, somewhat blurry, is her own head, bent over a notebook and a splay of open textbooks on the table. Derek must have been at the other end during one of her study sessions, and she must have been so engrossed that she didn't even notice him. During a study binge that's possible, even though she pretty much always notices him.

But, she realizes as she clicks on another picture, and another and another—it seems that she never notices him when he's behind a camera lens. But _he_ notices _her_.

Contemplatively, she closes the folder and looks at the homework spread out in front of her. So quickly she's not sure whether it was inadvertent or if she did it on purpose, she glances to the space under his bed where she knows there's a hidden piece of her clothing. She chews on her bottom lip and closes up her textbook.


	9. Chapter 9

**Saturday**

Most of Saturday passes by uneventfully as Derek and Casey try to avoid each other while forced to be around each other, resulting in an awkward tiptoeing that eventually results in their usual bickering. Finally, George empties his wallet and tells them to go see a movie.

" _One Bright Day In the Middle of the Night_?" Casey recites disdainfully. "No way, Derek. We're not seeing a horror film."

Ignoring her protests, Derek goes up to the window and buys the tickets, and then drags her to the concession line. Finally, she follows him into a darkened theater and they find a pair of seats in the back, and Casey resentfully sits down and forces him to open her box of candy. He rolls his eyes and steals some of her Skittles.

When the theater darkens entirely and the screen brightens with the opening of the movie, Casey takes a deep breath, bracing herself. Derek snickers quietly, and she throws a piece of popcorn into his hair.

Halfway through, spindly fingers glint silver in the moonlight, and Casey squeals and digs her nails into Derek's sleeve, and his attention becomes focused on her hand while his muscles tense. A moment later she buries her face in his shoulder as the music crescendoes, and without really thinking about it Derek pulls his arm from her grip and wraps it protectively around her shoulders.

When the screen blacks out and the credits finally roll, Derek pries Casey's fingers from where they're knotted in his shirt, and gently pushes her away so he can stretch his sore shoulder. "Movie's over. You lived."

"No thanks to you," she mutters, still miffed over his insistence on the horror movie and completely glossing over the fact that she spent the last half of the film clinging to him. Derek shrugs, smirking, and throws away the empty popcorn bucket.

When they arrive home, the house is dark and silent, the family having already gone to bed. Casey and Derek look at each other in the darkened foyer, and take the opportunity to jostle their way up the stairs and into their own bedrooms, thinking they can just switch early in the morning, or else just endure another day of punishment. At this point, anything to have their own space again, just for the night.

Casey closes and locks her door and immediately sits down in the desk chair she's been missing all week. Her own desk, white wood and perfectly organized, with a pretty paper flower from Lizzie in a glittery vase that Marti made in a summer camp crafts class. Maybe a little less organized since _Derek_ has been staying in her room, but, still more appealing to her than his space!

Derek closes and locks his door and immediately flops down onto the bed he's been missing since he stopped sleeping in there because of the baby assignment. The bed is a little too made, and the room smells a little too fresh and flowery, thanks to _Casey_ , but it's his own bed, in his own space, with the dark colors that don't hurt his eyes and the cool posters, and state-of-the-art stereo just within reach. And anything that is Derek's is better than anything that is Casey's.

After soaking it all in, he gets up and moves to his computer. The desk is too neat, stacked with Casey's binders and books stacked, and he shoves those out of the way and grabs the mouse. After a moment, the screen wakes up.

Derek shoves his chair back and rushes for the door.

After she's done straightening the things that are already straight on her desk, and adjusting the vase so that the flower is positioned just so, Casey gets up to flop down on her bed. It might be a little less made than she'd prefer, and Derek's mattress might be a little softer, but she's been missing the silky, weightless sheets and the cheerful colors she picked out herself. Her cheerful personality is much better matched to her own room than to Derek's.

She rolls over and cuddles one of her throw pillows, curious as to why this one is not tossed carelessly on the floor with the others. Pulling it to her chest reveals what's waiting underneath, and she throws the pillow aside and rushes for the door.

Derek and Casey meet in the middle of the hallway. Blue and brown eyes that could not be more different now wear expressions that could not be more similar in their shifting between surprise and confusion and anger and uncertainty. They look back and forth between Casey's room, Derek's room, Casey's room, Derek's—until Casey yanks Derek forward into her room and slams the door. Immediately they commence fighting.

"Der- _ek_ , you read my diary again—!"

"Maybe I did _this_ _time_ , but—!"

" _Every_ time—!"

" _You_ read through a private folder on my computer—!"

"You can't _read_ through _pictures_ , Derek—!"

They go at it until they're tired of shouting, and then Casey raises her hands to swat at Derek's hair, his face, his chest, and he grabs her by the arms to shake her, until somehow, suddenly, her lips are on his and his hands are in her hair and her fingers are curled in his shirt, and he slams her against the wall and she wrestles him to the bed and they end up on the floor in a tangle of limbs and confusion.

They sit up, disoriented from the impact, and the instant they look at each other they scramble apart.

Silence passes, broken only by the sound of panting as each tries to catch their breath, eyes locked and then broken away and then looking back again and away.

"Shit, shit, shit," Casey breaks the silence, getting to her feet and starting to pace around the room. Derek scrambles up and flips the lock on her door, and grabs her by the shoulders to stop her.

"Casey, if you start to freak out about this, your mom and my dad will find out and then we will be dead. _Dead._ " Derek's grip tightens, his fingers digging into her skin, until she's uncomfortably trying to twist away. "No, Casey, _look_ at me. Breathe. In…out…"

"I know how to breathe!" she snaps, shoving him away. She breathes in raggedly, then out, until Derek rolls his eyes and finds a paper bag for her to hyperventilate into.

Finally, Casey takes calmer, deeper breaths, and tosses the bag into the trash can below her desk. She balances her hands on either side of the bed next to her, staring at the rug, and says quietly, "I think you should go."

"What?" Derek reaches to touch her hand and she snatches it away before he can make contact. "Casey—"

"Derek, we _can't_ do this. For…for the sake of the family, what just happened can never happen again."

"For the sake of the _family_? _Really_ , Casey?" He gives her an incredulous look. "Why don't you just admit that you're scared and the family has nothing to do with it. Where was your consideration of the _family_ ten minutes ago!?"

"Der—" she tries, but he's already stormed out of her room, and slams his door shut so that one of his do not enter signs falls to the ground.

Biting her bottom lip, Casey stares at the sign on the floor. Then she gets up, goes to her own bedroom door, and closes it.


	10. Chapter 10

**Sunday**

"Is there a reason that you and Derek slept in your own rooms last night?" Nora raises an eyebrow at her oldest daughter, taking a long sip from her coffee mug, and Casey gulps down the bite of cereal she just took and offers a quick shake of her head, avoiding eye contact.

"I see." Nora folds up the newspaper in front of her. "Well, I'll have to talk to George about whether or not to extend the punishment by a day, since you know that's not what we agreed to."

"Mom—"

" _But_ , maybe if you and Derek can manage to be on your best behavior, together, for the rest of the duration, that won't be necessary." Nora fixes Casey with a _look_ , and Casey focuses on her breakfast, face reddening in shame.

As soon as Nora leaves the room, though, Casey exhales the tension in her shoulders and stirs her spoon around. If only her mother knew how easy it could be for Derek and her to behave, since they've managed to completely avoid each other since last night.

Maybe if she sneaks out of the house now, though, she can keep avoiding him. _Smelly Nelly's is open._ She can go there to study.

Leaving her cereal bowl where it is on the counter, she sneaks upstairs to grab her books, and leaves out the back door. She pauses just outside, realizing she didn't put her bowl in the sink, and with great effort she shrugs and keeps going down the sidewalk. Nora and George already ruined everything for her, so let them deal with it.

A couple of hours later, she's set up in a booth at Smelly Nelly's with books and papers carefully strewn across the table, and a mug of coffee and a bottle of water within easy reach. The pile of "done" homework is slowly outgrowing the pile of "to do," and she's just looked up in search of a waitress to flag down for more coffee when somebody slides into the seat across from her.

Casey sighs and returns her gaze to the pile of papers she's shuffling around. "What do you want?"

"There are a lot of ways I could answer that question, Space Case," Derek says matter-of-factly. "But I'll start with 'a cup of coffee.'"

A redheaded waitress wiping down the table in the booth behind them perks up at Derek's request and quickly moves to stand next to him, writing down his order. "Can I get you anything else?" She smiles sweetly, and Derek puts up two fingers.

"Make it two cups of coffee. One for the lady."

"Certainly. You know, you two make such a cute couple."

"Thanks." He tries to smirk, but instead is unable to contain the smile that stretches across his face. The waitress puts away her notepad and sashays away, and Casey glares at Derek.

"'A cute couple?'" she hisses. "Really?"

He shrugs, palms turned up in a gesture of innocence. "She came to that conclusion all on her own."

She ignores him now, eyes focused on the pages of one of her English textbooks while her hand scrawls notes across a piece of lined paper. Calmly, Derek reaches out and plucks the pen from her fingers, and Casey slams her hand flat on the table.

"Der- _ek_!"

" _Talk_ to me, Casey."

"Talk about _what_?"

"The _kiss_ , Casey!"

She stiffens, and when he reaches for her she flinches away.

"What's there to talk about?"

He bites down on the inside of his cheek until warm blood spills into his mouth, in an effort to restrain himself from crossing to her side of the booth and shaking the sense back into her. Instead, he just gives her a pointed look.

" _What_ is there to talk about, Derek? Fine, we kissed. It was a mistake, which no one can know about, and it can never happen again."

"You're _overthinking_ it, Head Case!"

At that exact moment the waitress returns and deposits a cup and saucer on the table in front of Derek. She fills his mug and then Casey's, and then scurries away with her head down, apparently having overheard Derek's outburst.

Casey pulls her cup closer to her chest while glaring at her step-brother. "You're not thinking about it at all, Derek!"

"Casey," he scoffs, "I've been thinking about it for _months_!"

She freezes with her cup of coffee halfway to her lips, and Derek softens his voice. "And I know you have, too."

She swallows and puts the cup down without having taken a sip. "It doesn't matter what I've been thinking. What matters is that this— _we_ —can't happen, Derek! Mom and George would be _furious_ , it would freak out Lizzie and Edwin, and Marti—"

"Marti would be _fine_ ," he insists. "And I know Edwin, and he and Lizzie would be fine, too. So the only unknown variable would be—"

"Mom and George," she finishes with a sigh. Then she gives him a quizzical look. "Wait—when did you start using terms like 'unknown variable?'"

"I pay attention in math," he defends. She raises one eyebrow, and he raises one back at her, and she reddens as she realizes that math is the class that she sits _in front_ _of_ Derek in. Evidently it's not the teacher he's been paying attention to—but maybe he's still picked up a few things.

"Derek…" Casey trails off, thinking about what he's saying. Has it really been months for him, too?

"Just think about it, Casey. Okay?" Derek slides out of the booth and stands up, tossing a few crumpled bills on the table, enough to cover the cost of both coffees. Casey looks from the money to him and back again, and he smirks at her. "I'll see you at home."

 _In my room or yours?_ The quip is instantly at the tip of her tongue but she bites it back and instead only nods—but she can't keep the ghost of a small smile from her lips.


End file.
